This invention relates generally to an elevator position sensing and control system, and more particularly involves a method and apparatus for determining the position of an elevator car in an elevator shaft relative to a landing and for controlling the speed of the car and the positioning of the car at a selected landing.
Conventional elevator position sensing systems employ metal vanes which are attached to the elevator shaft wall adjacent of each landing to indicate the approach and location of each landing. Typically the metal vanes protrude into the shaft to a location in the vicinity of the car's path, and magnetic sensors on the car detect the vanes. The detection information is used for controlling the speed and positioning of the car. In such a system a plurality of metal vanes must be installed at each landing, and the installation and alignment of these vanes is very time consuming and therefore expensive.
In U.S. Pat. No. 3,815,711 of Hoelscher a vane control system for elevators is described, in which a light sensor array is used to detect the presence of a vane as it passes through the sensor array to interrupt the illumination of each sensor in turn. Again this involves positioning of vanes in the elevator hoistway adjacent each floor of intended landing.